To install the plugin, head over to the machine with Homebridge set up and run

sudo npm install -g homebridge-sonytvon

To make Homebridge aware of the new plugin, you will have to add it to your configuration usually found in .homebridge/config.json. Somewhere inside that file you should see a key named accessories. This is where you can add your tv as shown here:

"accessories": [
    {
      "accessory": "Sony",
      "name": "Living Room TV",
      "mac": "<mac-address of your TV>",
      "ip": "10.0.1.23"
    } 
]